.mino, .innerSquare{
  position: absolute;
  box-sizing: border-box;  
}

.mino{
  z-index: 1000;
  border: 2px black solid;
}

.innerSquare{
  top: 15%;
  height: 70%;
  left: 15%;
  width: 70%;
  border: 1px black solid;
}